Weed control protects remnant forest on Kaikōura Plains

Photo: Heath Melville - South Island robin are present in Kōwhai Bush

Problematic pest old man’s beard has been targeted for weed control in Luke Creek, Waimangarara and Kōwhai Bush to preserve and enhance existing biodiversity values.

All three areas are ecologically rich in biodiversity and have many native bird species present including pīwakawaka/fantail, miromiro/tomtit, riroriro/grey warbler, pīpipi/brown creeper, tauhou/silver-eye kōtare/kingfisher, pīpīwharauroa/shining cuckoo, kererū/New Zealand pigeon, ruru/morepork, tūī, korimako/bellbird, kakaruwai/South Island robin and tītitipounamu/rifleman. The work builds on previous efforts to clear weeds.

Protecting native plant species

Photo: Heath Melville - Aerial image of Waimangarara weed control area

Kaikōura land management and biodiversity advisor Heath Melville said protecting the natural values at these sites is particularly important as they provide habitat for a wide range of species.

“Ongoing weed control is vital here to protect these valuable patches of bush, which support such a broad range of species such as the South Island robin,” he said.

“These are some of the few remaining examples of native forest on river gravels in the eastern South Island. While there are vast areas choked in beard and other weeds, there has been a lot of work over the years to look after the most-valuable areas, particularly in the Kōwhai reserve.”

With less than 20% of native cover remaining in this area, it is important to take actions to protect and enhance the remaining native vegetation, birdlife and invertebrate species that reside there, and those that the habitat supports. 

Kōwhai Bush control protecting native species

Weed control in Kōwhai Reserve (left), Luke Creek (middle) and Waimanagarara Reserve (right) helps protect some of the last remaining native remnant forest across the Kaikōura Plains

Kōwhai Bush is one of the few remaining examples of native forest on aggregate river gravel in the eastern South Island. It hosts native plants like kānuka, māhoe, whauwhaupaku/five-finger, pittosporum and podocarps such as mataī, and tōtara in the older patches of forest.

It is home to the South Island robin and rifleman, both species considered rare for the area. Brown creeper, bellbird, fantail, grey warbler, silver-eye, tūī, tomtit, kererū, morepork and shining cuckoo are also present.

Kōwhai Bush and Luke Creek provide an important link between the coast and the DOC estate of Mt Fyffe and the Seaward Kaikōura ranges. With native forest fragmented across the plains, the area provides important habitat for the native birds, so it’s important that we protect the area from pest weeds and animal.

Work to control old man’s beard in Kōwhai Bush is being carried out and to a lesser extent darwin’s and common barberry, douglas fir, sycamore, ivy, hawthorn, blackberry and more. 

Luke Creek weed control is focusing on old man's beard, himalayan lily and banana passionfruit. In Waimangarara, old man’s beard and cathedral bells are being targeted.

Weed control work is carried out on many other Environment Canterbury reserves throughout the region, and in many different types of habitat including wetlands, drylands, estuaries, and riparian areas. Weeds that make the most impact are controlled first, with the control area expanded or further species added to the control list as resource and funding are available. 

Targeting old man’s beard

Ongoing control of old man’s beard around the region’s reserves and parks is particularly important, especially where it threatens the few remaining reserve lands with native forest cover.

Old man's beard can fundamentally change the habitat it is invading, multiplying rapidly and crowding out native plants, smothering mass over trees and shrubs, blocking out light and eventually killing supporting plants. It is a vigorous growing vine and can destroy high value biodiversity and ecological sites.

One plant can blanket an area of 180 sqm. It seeds profusely and the seed can remain viable in the soil for several years. Stems can provide up to 10 metres of growth in a season.

Weed control programmes are designed to protect the most susceptible native species and limit weed spread to neighbouring properties or reserves.

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